Re: Towards a definition of atomic
From: Marshall <marshall.spight_at_gmail.com>
Date: Fri, 1 Feb 2008 10:02:39 -0800 (PST)
Message-ID: <73784604-2d25-4e53-a869-2b033207deea@e4g2000hsg.googlegroups.com>
> The important thing in this discussion is: The relational model treats
> domain values as neither composable nor decomposable. They are
> simply values upon which one may evaluate defined operations.
Date: Fri, 1 Feb 2008 10:02:39 -0800 (PST)
Message-ID: <73784604-2d25-4e53-a869-2b033207deea@e4g2000hsg.googlegroups.com>
On Feb 1, 8:15 am, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
>
> The important thing in this discussion is: The relational model treats
> domain values as neither composable nor decomposable. They are
> simply values upon which one may evaluate defined operations.
If one goes just a bit further, one might say the only such operator is equality, which is clearly necessary for natural join, etc. A theta join, for example, is a join of two operand relations and a further join with the < relation.
Marshall Received on Fri Feb 01 2008 - 12:02:39 CST